Study On Chemical Looping Co-production Of Hydrogen And Syngas Based On Nickel Ferrite

Hydrogen,as a renewable low-carbon energy carrier,has attracted much attention.By adjusting the ratio of fuel and oxygen carrier in the fuel reactor of the chemical looping hydrogen production technology,the co-preparation of hydrogen and syngas can be realized,which greatly improves the fuel utilization efficiency and has a good development prospect.NiFe₂O₄has good catalytic performance and high reaction activity,and can be used in the process of co-preparing hydrogen and synthesis gas in chemical looping technology.In this paper,using toluene as fuel and NiFe₂O₄as oxygen carrier,an experimental study on the co-preparation of hydrogen and syngas by chemical looping technology was carried out.The main conclusions are as follows:（1）Explore the effect of different preparation methods on the performance of NiFe₂O₄:NiFe₂O₄were prepared by solid state method（SS）,sol-gel method（SG）and co-precipitation method（CP）.Through characterization analysis and chemical chain co-preparation of hydrogen and synthesis gas experiments,the results show that the sol-gel method is the best NiFe₂O₄preparation method.（2）Based on the principle of Gibbs free energy minimization,the process of hydrogen and syngas synthesis by chemical looping was analyzed.NiFe₂O₄was reduced and oxidized step by step during the test.Temperature and oxygen supply coefficient are obvious influencing factors.When the oxygen supply coefficient is constant,appropriately increasing the reaction temperature is conducive to the deep reduction of iron and improving the gas production effect.When the temperature is constant,appropriately increasing the oxygen supply coefficient is conducive to improving the synthesis gas yield,hydrogen purity and yield and other indicators.（3）Using toluene as fuel and NiFe₂O₄as oxygen carrier,the best reaction conditions were explored.The best reaction conditions were reaction temperature 850℃and oxygen supply coefficient 0.5 and the ferrite prepared by sol-gel method were involved in the reaction.If water vapor is added in the FR stage,the optimal water-carbon ratio is 0.6.（4）NiFe₂O₄was modified with metal elements Mg,Co and Cu,and Ni_1-xMg_xFe₂O₄、Ni_1-xCo_xFe₂O₄、Ni_1-xCu_xFe₂O₄（x=0.2、0.4、0.6 and 0.8）were generated.The performance of syngas and hydrogen production was studied under the best working conditions.The results show that Ni_0.4Co_0.6Fe₂O₄has the strongest effect on improving gas production.